Packages and Parts

An Office Open XML document is represented as a series of related parts that are stored in a container called a package. Information about the relationships between a package and its parts is stored in the package's package-relationship ZIP item. Information about the relationships between two parts is stored in the part-relationship ZIP item for the source part. A package is an ordinary ZIP archive, which contains that package's content-type item, relationship items, and parts. (Packages are discussed further in Part 2.)

A WordprocessingML document contains a part for the body of the text; it might also contain a part for an image referenced by that text, and parts defining document characteristics, styles, and fonts. A SpreadsheetML document contains a separate part for each worksheet; it might also contain parts for images. A PresentationML document contains a separate part for each slide.